The suspect, later identified as an emotionally disturbed homeless man named Julius Graham, attacked a father, his 2-year-old son and three other people in a series of random attacks along one of the park's running and biking paths.
"He was looking for people he could mess with," an eyewitness told the New York Daily News. "He was looking for trouble."
Graham allegedly began his spree by stabbing a 36-year-old woman in the back. His next victim was a 36-year-old man, whom he slashed in the stomach. He also slashed a 32-year-old jogger's neck.
“She was screaming and was holding a coat over her neck," a witness said of the female victim. "She told me she was stabbed. She was hysterical, crying.”
Passerby Thomas Ciriacks was walking this dog when he saw Graham attacking James Fayette, a 35-year-old man pushing his young son along the path in a stroller.
According to DNA Info, Ciriacks managed to pin Graham to the ground and hold him there until police arrived.
"I'm no hero," Ciriacks said of his efforts. "The real hero is the guy with the kid."
All five of the Riverside Park victims are expected to survive the attack.
Police Commissioner Raymond W. Kelly said that Graham was in custody at Bellevue Hospital Center.
The stabbings come just days after a man approached a female jogger in Washington Heights' Fort Tryon Park. The woman, who was pushing her child in a stroller, hit the man with a bicycle pump. Though Kelly reassured New York City residents that they could continue to enjoy their public parks.
“Parks are very, very safe,” Kelly said. “We see something like this happen and it concerns everybody, we understand that. But the amount of incidents of crime in parks is minuscule.”